Electrode holder



4 Sheets-Sheet l F. LEHRER ETAL ELECTRODE HOLDER Filed oct. 4, 1940sept. 29, 1942.

,Y 2574 I a le l' 2q 1 r 9 i Y. Ja

j, VF

Jv* LL o` Sept. 29, 1942. F. LEHRER ET AL 2,297,484 ELEGTRODEl HOLDER IFiled Oct. 4, 1940 4Sheets-Sheet 2 Sept. 29, 1942. F. LEHRER ET A1.2,297,484

` ELEGTRODE HOLDER Filed oct. 4, 1940 4 sheets-sheet s Sept. 29, 1942.

F. I EHRERy ET AL x-JLECTRODE HOLDER Filed Oct. 4, 1940 4 Sheets-Sheet 4saggE I Patented Sepb29, 1942 v UNITED STATES; PATENT 1 OFFICE hannesWotschke,' Berlin-Dahl em,Germany;

vested in the Alien Property Custodian 2 Claims.

The invention relates to electrode holders consisting of twospacedsuperposed clamping Jaw arrangements and with the aid of such.a pair ofclamps the electrode held therein is automatically finely adjustablewhen being ied, without loss of gripping security in all operating andregulating positions. According to this invention the superposedclamping arrangements are connected with leach other, are positivelylocked and move in opposite directions preferably in such a manner thatall force transmitting components are engaged only with respect to pullor pressure. The clamps may be provided with any number of jaws and alsomay be designed for current transmission, the part' holding theelectrode being of a design known-for such purpose.

'I'he positively locked connection of the two clamps moving in oppositedirections has the eiect that the gripof the lower clamp holding theelectrode in operating position is'necessarily weakened in the case of acontemplated readjustment of the electrode but only to such a slightextent that the electrode moves relatively to such clamp and, in fact,tothe entire A holder owing to the fact that the .starting of there-adjusting movement for loosening one of the clamps results in acorresponding pressingon effect of the other clamp. In consequencethereof the feeding movement may be nterrupted at any place andtherefore may be as slight as desired. At the end of the adjustingmovement the pressing-on force, stopping the electrode, will by itselfincrease again to the original value. The invention in view of thiseffect may be designated as a sliding holder with automatic regulationand ne adjustment. The drawings show the invention in several modes ofconstruction in lateral view and the individual components in sectionalview. Corresponding components in the various figures are provided withthe same symbols.

Figure 1 shows a simple mechanical design of the new sliding holder.

Figure 2 shows a sliding holder with mechanical force-operatedarrangement-'and common actuation of all re-adjusting members of theupper clamp. l

Figure 3 shows a hydraulically actuated sliding holder.

Figures 4, 5 and 6 represent in longitudinal section and greatlyenlarged the bearing of a drawbar in various positions.

Figure 7 shows in centre longitudinal section with individual componentsa fourth mode of construction according 'to the invention.

In Figure 1 the electrode I., which simultaneously may be designed forcurrent transmission, is spring held by jaws, the spring power beingadjustable as to its value by means of a rod arrangement for subjectingthe jaws to pressure. For this purpose the tension of spring 2 istransmitted in the casing 1 by way of the crosshead "trode will increasein keeping with the increase of the force acting in downward directionon the legs II of the tongs. With an upward movement of the tongs themouth I4 of the tongs tends to open in response to the effect of themoment caused by the frictional force and thus opposes the upwardmovement by a but very small force scarcely impeding such movement. Thebar 8, on which the spring 2 is exerting its compressive force, passesthrough this spring and its upper part is designed as a screw extendingthrough the legs II of the tongs. Thusa travelling nut I0 which, on theone hand, is screwed onto the spindle 9 and, on the other hand, isrotatably connected to the leg II of the tongs, with a movement of thespindle 8 takes compulsorily with it the leg I I of the tongs. Onturning the nuts simultaneously, for example, over a chain drive I3, thenuts will at rst move downward only as far as is permitted by thebacklash. Downward ,sliding oil of the tongs is prevented by theirautomatic stopping. Thus, continued turning of the screws will result ina pulling force opposed to and weakening the spring power. The'pressureat the jaw 6 is thus reduced, but the downwardly directed weightv of theelectrode I, having so far been balanced by the frictional force causedby the spring power at the jaws, is augmented by the reactive forcetransmitted by the tongs I4 to the electrode I, causing sliding of theelectrode. The electrode continues to slide as long as the equilibriumis interfered with by the turning of the screws. On ceasing turning thescrews I0, the force weakening the springs 2 caused by the turning ofthe screws will diserated eiect cannot occur with this movement betweenthe tongs and the electrode.

The preferably water-cooled holding ring 8 may be either rigidly mountedor in known manner be moved up and down. One conventional method ofmounting the holder together with the electrodes involves the use of theeyes I6 and cables I1 which run on pulleys I8 and can be wound up on thedrum' I9 by a motor.

' This design requires but a very slight height. The electrode may beuniformly released by any amount without interrupting the current. Butwith known, types, although they are operating without currentinterruption but must completely release the jaws, there is danger of anelectric are being formed between the jaws and the electrodes. Thisdisadvantage is avoided by the invention.

In the design according to Figure 2 the electrode I is heldin restposition by the four jaws 6 of the lower clamp holder. For this purposethere are arranged in cups the springs 2 exerting a compressive eiect onthe bars 9. The spring pressure is transmitted to the plungers 5 bymeans of the links 3 and the toggle 4. The arrangement 2 to 1 isaccommodated in a cooled ring-shaped casing 1 carrying in its upper partremovable and follower-like closed spring heads 3|).l Tension of spring2 may be adjusted by adjustment of bolts acting upon spring head 30. Atthat place are also suspended in hinged arrangement the jaws 6. Theupper clamp carries the jaws Il on bars or holders II on which arerotatably fastened the spindle nuts Ill. The chain I3 in this mode ofconstruction serves for the common actuation of all the nuts I0.

In order to supply electric current to the electrode II, a currentlead-in '23, water coolednis connected with the jaw 6.`- Numeral 24designates the exible leads connecting lead-in 23 with a current sourcenot shown.

jaws Ii are electrically connected to each other,-

said jaws being ilexibly suspended to the holding ring by means ofa link20 and joints 2I.

Since the nature of the invention involves transmission of occurringclamping forces and liberating -forces in the mechanically simplestform, namely, by pulling forcesor compressing forces, and to keep thetransmitting components at least theoretically free from bendingstresses, importance is attached in all modes of construction to guidingall screw spindle bars 9 perpendicular and exactly parallel to oneanother. For thisreason also the legs of the vtongs (holders) which arerotating, though but slightly, around their axis of rotation-due forexample to elastic deflection of the'holders, unequal thickness of theelectrodes, blacklash at the axis of rotation et cetera-must beconnected to the ball joint comprising the ball members I0 and ball cupIII with the screw spindle bars by an intermediate member. The Figures4, 5 and 6 show the eiective and extreme position of the ball joint -inexaggerated representation. The spindle system at the spindle heads isstiffened by a ring in consequence of the fact that in practical design75 vare the spindle nuts III, the chain I3 serving for The various thereare transmitted to the spindle also over the ball joint and the bearingsurface, respectively, slight frictional forces between the ball cup andthe nut, which would exert a bending strain on the spindle.

According to the invention the especially simvple` design according toFigure 3 embodies a nnemeans on piston 5u. through conduit 5b (shown onthe left hand side of the drawing) and a spring 2, described in theforegoing, or an elastic pressure means, such as compressed air over thepiston infequilibrium. as described in the foregoing. The upper clampsI4 are arranged in holders II (compare Figure 4); I3 is the commonactuation f or the spindle nut I0. Nut I0 acts upon holder I I throughangle member 29, see Figures 1 and 2 as well as Figure 3.

From a pressure means tank, not shown, is conducted a noncompressiblemedium (water, oil) through the shut-oil" valve 3I into the pressurecylinder communicating with the piston which is filled until thepressure piston assumes about the position shown in the drawings. Whenin this position the shut-olf element is closed and used laterexclusively for reiilling if there has occurred a loss of pressuremeans. if any. The spring 2 is tensioned to such an extent that thepressure exerted by it over the pressure piston produces a bearingpressure of the piston 5 on the jaw 6 permitting of holding -the weightof the electrode. The mode of operation of the upper clamp is again thesame. Turning the screw over a common driving means, for example, thechain I3, exerts a pulling force on the spindle 9, owing to the factthat the upper .clamp is self-stopping, and relieves the pressure pistonwhose reduced pressure adapts itself to the piston. The .pulling force'at the spindle transmitsitself as reactive force over the upper clamp tothe electrode and increases the weight of the electrode--the electrodeslides. The screws having been set at rest, the spring regains itsoriginal tension and thereby also the press' ing-on force will beregaining its original value which will he able to maintain theelectrode in portingf ring Bare suspended the jaws 6-of the I the restposition. Equilibrium is re-established. The design according to Figure7 shows an especially completely equipped development.

The circular casing 1 is designed as protective` jacket. At its cooledcover in form of the suplower clamp for vthe electrode I, simultaneouslyserving for current supply. The protective jacket 'I contains also thelower ends, loaded by the pressure springs 2, of the spindle bars 9,jointly carrying a wedge-shaped ring 32 coacting with the correspondingVcounter wedges 22 cast or other-l wise attached on the outer surface ofthe jaws' 6. The sleeve I5 serving for permitting the passing of thescrew spindle 9 through the carrying ring 8 serves simultaneously foraffecting the tension their common drive. The perpendicular position ofthe spindle nuts Il) opposite the jaws I4 with the readjusting motion inthe sense of the maintenance of. pure compression forces and pullingforces, is also secured in this mode of construction by a crownedintermediate bearing similar to that shown in Figure 4. The eyes I6 atthe carrying ring 8 are serving for the suspension of the-entirearrangement.

The spring 26 of Figure 2 and the spring 26a of Figure '7 serve toincrease 'the clamping effect of the tongs when the electrode is to bemoved downward and it is necessary'toavoid lifting the tongs too faraway from the electrode when nut I0 is traveling upward,

Corresponding to the designs described in the foregoing, in their restposition, namely, in the operating position, the jaws 6 of the lowermain clamp are rmly pressed against the electrode I. For this purpose isserving the keying between the outer surface of the jaws and thewedgeshaped ring, assisted by the springs 2. When rotating the spindlenuts I0 by actuating the chain I3, so that the spindle 9 is liftedagainst the action of the springs 2, the pressing-on of the wedgeshapedring and corresponding thereto the clamping effect of the jaws will bedecreased. But at the same time the spring load of the spindle 9 and itsnuts I0 will be augmented by the tension of the springs 2. The spindlenuts will press to the extent of their rotation over their crowned baseon the holders of the auxiliary clamping jaws I4, pressed accordinglyagainst thev electrode.

What is claimed isi 1. An electrode holder comprising, a main clampdesigned as a current conduit for holding an electrode in operatingposition, means for supporting said main clamp, a secondary clampaxially spaced from said main clamp and adapted to act on anotherportion of an electrode, means normally pressing said main clamp intogripping position, and means acting on said last-named means for drawingsaid two clamps together and simultaneously displacing the pressurethereof from the main clamp to the secondary clamp to permit passage ofthe electrode through the former.

2. An electrode holder comprising, a main clamp designed as a currentconduit for holding an electrode in operating position, means forsupporting said main clamp, a secondary clamp laxially spaced from saidmain clamp and adapt--l ed to act on another portion of an'electrode, a

rod operatively connecting said clamps, a spring acting through said rodto normally bias the main clamp to gripping position and the secondaryclamp to release position, and means for simultaneously shortening theeffective length of said rod and compressing said spring to relativelymove said two clamps toward one another and to displace the thrust ofsaid spring from said main clamp to said secondary clamp to permitpassage of the electrode through the former.

FRITZ LEHRER. 1 JOHANNES WOTSCHKE.

